Hey Razor,
Hmmm, on the disclaimer issue I do it mainly not to alienate readers and to avoid subjecting people to the kind of content that would deeply upset them. People always have a right to opt out of this sort of thing and you while you can stop reading, you can't really "unread" what you've already read.
Since there are so many people who have had genuine rape experiences, abuse experiences, and real personal trauma, I believe personally that it would be wrong for me to risk subjecting such a person to a possible reliving of said bad experiences through my fiction if it was not their choice to do so. (i.e. someone may have HAD a bad experience and still choose to read after the disclaimer and it may or may not be therapeutic for them to do so, but it's their choice to make, not mine.)
However, that is MY morality. I cannot dictate to others what they should or shouldn't do with regards to disclaimers. As for legal liability, I'm not sure, I think in most public fiction there is a disclaimer to the effect of: "all events, places, situations, people are fictitious...blah blah blah"
There will always be the chance that some psycho later is gonna come along and say: "Well I got this idea to be an evil serial rapist from this story I read." So it can serve as a "cover ya ass" type deal, though I hardly think anyone can really hold someone responsible for fiction inciting criminals. If that were true, movies like Saw and Hostel could not legally exist.